Structure Of CdS Nanoparticles Research Articles

Enhanced photocatalytic degradation of methyl orange dye on interaction with synthesized ligand free CdS nanocrystals under visible light illumination.

Methyl orange is widely used dye in textile industry and later, it becomes the major component of industrial waste and pollutes different water body. So, its degradation is required especially in the case of drinking water. Here, chemically synthesized ligand free CdS nanocrystals have been utilized as a photocatalyst to degrade this dye in water. The mean size of the CdS nanocrystal has been found to be 7nm approximately from TEM analysis, and SAED pattern shows that these are crystalline in nature. Further, the XRD patterns confirms the cubic structure of CdS nanoparticles and mean size calculated from XRD analysis matches well with the obtained size from TEM study. NMR study clearly verifies that CdS nanocrystals are ligand free stable nanoparticles. Due to this absence of ligand on the surface of CdS nanocrystals, a much enhanced MO degradation has been observed, as the e--h+ pair in the CdS and subsequent generation of free radicals such as hydroxyl, can efficiently oxidize the organic material MO and therefore, degrade this pollutant faster under visible light illumination. The degradation efficiency is found to be 95% after 300min of illumination, which is much better than the other similar reports.

Effect of the size and structure factors on the magnetic susceptibility of nanoparticles of cadmium sulfide

The dependence of the Van Vleck component of the magnetic susceptibility of nanostructured cadmium sulfide CdS on the geometry and structure of CdS nanoparticles has been established by analyzing the data obtained from diffraction and magnetic measurements. It has been found that a decrease in the size of wurtzite CdS nanoparticles leads to an increase in the degree of distortion of the sp 3 orbitals (i.e., the degree of covalence), which reaches a limiting value for elongated particles with an average size of 9 nm. In particles with smaller sizes, the character of the orbital distortion sharply changes, and the Van Vleck contribution returns to the value typical of coarse-grained CdS. Nanoparticles less than 9 nm in size have a specific disordered close-packed structure and a centrosymmetric shape. The data obtained have made it possible to understand the reason of the dimensional phase transition from the crystalline state to a specific nanostate of cadmium sulfide.

Structural Phase Behavior and Vibrational Spectroscopic Studies of Biofunctionalized CdS Nanoparticles

Biomodified CdS nanoparticles were synthesized using l-cysteine as a capping agent in the colloidal state as a function of pH. The role of pH on the size and structure of CdS nanoparticles was investigated in detail. At pH 7.4 and 9.1, X-ray diffraction spectra of as prepared samples showed the presence of a mixture of cubic and hexagonal phases while cubic phase was formed at pH 11.2. A gradual transition to the hexagonal phase was observed for refluxed samples at pH 9.1 and 11.2. Whereas, at pH 7.4, the sample remains in a mixture of cubic and hexagonal phase even after refluxing. The particle size of as prepared samples was about 2 nm, and for refluxed samples the size increased up to 10 nm. The binding of cadmium through thiol group is evidenced by infrared spectra. An intense band due to C-C-N vibration was observed after 24 h of reflux. The formation of a specific molecular cluster determines the growth of a particular phase. Transmission electron microscopy (TEM) studies support the X-ray diffraction (XRD) studies and exhibit well separated spherical particles while refluxed samples show clustering.

Study of the thickness of a stabilizing shell absorbed on the surface of CdS nanoparticles

This paper discusses the size parameters and surface structure of CdS nanoparticles stabilized by organic shells. The thickness of the shells and the possible placement of the molecules of the shell on the nanoparticle's surface are measured.

A new approach to hybrid CdS nanoparticles in poly(BA-co-GMA-co-GMA-IDA) copolymer membranes

This study proposes new method for preparing hybrid CdS nanoparticles in poly(BA-co-GMA-co-GMA-IDA) (PBGM) copolymer membranes with controllable size. PBGM membranes were prepared by soap-free emulsion copolymerization of n-butylacrylate (BA), glycidyl methacrylate (GMA) and 2-methacrylic acid 3-(bis-carboxymethylamino)-2-hydroxy-propyl ester (GMA-IDA). GMA-IDA chelating groups within the copolymer were the coordination sites for chelating Cd 2+, at which nano-sized CdS nanoparticles were grown. The GMA-IDA mole fractions in PBGM1, PBGM2, and PBGM3 were 3.97%, 6.41%, and 8.79%, respectively, as determined by elemental analysis. Fourier transform infrared spectroscopy spectra were used to elucidate the characteristics of GMA-IDA in PBGM membranes. The size distribution, morphology, and structure of CdS nanoparticles were measured by transmission electron microscopy (TEM) and X-ray diffraction. TEM observations reveal that the mean diameters of CdS nanoparticles can be controlled between 3 nm and 6 nm inside the matrix of the PBGM membranes. The UV–vis absorption spectra provide information on the absorption edges, band-gaps and mean diameters, the results of which are consistence with the TEM observations. Photoluminescence spectra show the characteristics of excitation absorption of the hybrid membranes. Scanning electron microscopy images reveal the different sizes distributions of CdS nanoparticles on the surfaces.

Structure of CdS nanoparticles containing cadmium arachidate LB films

Y-type cadmium arachidate LB films were exposed to H 2S gas for different durations. UV-VIS absorption spectra reveal an absorption edge at 455–460 nm in a 30 min H 2S exposed film which does not change appreciably on further exposure. The blue shifted absorption edge is attributed to the formation of 30 Å CdS nanoparticles. The H 2S exposed films exhibit two types of layered structures, that is, the original bilayer spacing of 55.2Å as well as an additional bilayer spacing of 44Å. The XRD peak intensities corresponding to the new bilayer spacing (44Å) increase up to 6h of H 2S exposure accompanied by an increase in bandgap absorption. These results suggest that CdS nanoparticles are formed within domains having tilted arachidate molecules distributed throughout the film without completely destroying the original layered structure of the LB film.